Interference mitigation in an air-to-ground wireless communication network

ABSTRACT

A network for providing air-to-ground (ATG) wireless communication in various cells may include a receiver station disposed on an aircraft in flight, a plurality of base stations, each base station defining a corresponding radiation pattern such that the base stations are spaced apart from each other to define at least partially overlapping coverage areas, and a control module in communication with at least one of the base stations. The control module may be configured to receive information indicative of an altitude of the aircraft and select a frequency for communication between the at least one of the base stations and the receiver station based on the altitude.

TECHNICAL FIELD

Example embodiments generally relate to wireless communications and,more particularly, relate to mitigation techniques for wirelessair-to-ground (ATG) networks.

High speed data communications and the devices that enable suchcommunications have become ubiquitous in modern society. These devicesmake many users capable of maintaining nearly continuous connectivity tothe Internet and other communication networks. Although these high speeddata connections are available through telephone lines, cable modems orother such devices that have a physical wired connection, wirelessconnections have revolutionized our ability to stay connected withoutsacrificing mobility.

However, in spite of the familiarity that people have with remainingcontinuously connected to networks while on the ground, people generallyunderstand that easy and/or cheap connectivity will tend to stop once anaircraft is boarded. Aviation platforms have still not become easily andcheaply connected to communication networks, at least for the passengersonboard. Attempts to stay connected in the air are typically costly andhave bandwidth limitations or high latency problems. Moreover,passengers willing to deal with the expense and issues presented byaircraft communication capabilities are often limited to very specificcommunication modes that are supported by the rigid communicationarchitecture provided on the aircraft.

As improvements are made to network infrastructures to enable bettercommunications with in-flight receiving devices of various kinds, it ispossible that interference problems may be encountered. In particular,for solutions involving unlicensed band communication in the skies overmetropolitan areas, it may be reasonably expected that the presence ofWiFi transmitters distributed over such areas may create a verychallenging communication environment. In fact, the amount ofinterference over larger metropolitan areas could be quite large basedon the expected number and density of transmitters.

BRIEF SUMMARY OF SOME EXAMPLES

The continuous advancement of wireless technologies offers newopportunities to provide wireless coverage for aircraft at varyingelevations. Some example embodiments may provide interference mitigationtechniques that may incorporate the use of different frequencies forcommunicating with airborne receivers on the basis of the altitude ofthe receivers. Thus, for example, altitude bands may be defined anddifferent frequencies may be prescribed for communication with targetsthat lie within corresponding different altitude bands.

In one example embodiment, a network for providing air-to-ground (ATG)wireless communication in various cells is provided. The network mayinclude a receiver station disposed on an aircraft in flight, aplurality of base stations, each base station defining a correspondingradiation pattern such that the base stations are located at intervals(e.g., spaced apart) from each other to define at least partiallyoverlapping coverage areas, and a control module in communication withat least one of the base stations. The control module may be configuredto receive information indicative of an altitude of the aircraft andselect a frequency for communication between the at least one of thebase stations and the receiver station based on the altitude.

In another example embodiment, a method of communicating in an ATGnetwork is provided. The method may include receiving dynamic positioninformation indicative of at least an altitude of an in flight aircraft,determining an altitude band in which the aircraft is located based onthe dynamic position information, determining a frequency associatedwith the altitude band in which the aircraft is located, and selectingthe frequency to conduct wireless communication with an asset on theaircraft.

In another example embodiment, a network for providing ATG wirelesscommunication in various cells is provided. The network may include abase station array and a sky cell. Each base station of the base stationarray defines a substantially horizontally extending radiation pattern.Additionally, base stations of the base station array are located atintervals (e.g., spaced apart) from each other to define at leastpartially overlapping coverage areas. The sky cell comprises acircularly polarized antenna array defining a substantially verticallyextending radiation pattern that overlaps with at least one coveragearea of a base station of the base station array. The network isconfigured to conduct a handoff of a receiver station on an aircraftbetween the base station of the base station array and the sky cellbased on movement of the receiver station.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 illustrates a top view of an example network deployment providingair-to-ground (ATG) wireless communication coverage areas in accordancewith an example embodiment;

FIG. 2 illustrates an aspect of an example network deployment of basestations providing overlapping cell coverage areas to achieve coverageup to a predetermined altitude in accordance with an example embodiment;

FIG. 3 illustrates an aspect of an example network deployment of basestations providing overlapping cell coverage areas and/or additionalcoverage areas in accordance with an example embodiment;

FIG. 4 illustrates a side view of a coverage area of a verticallyoriented cell or “sky cell” in accordance with an example embodiment;

FIG. 5 illustrates a functional block diagram of an ATG communicationnetwork that may employ an example embodiment of a beamforming controlmodule;

FIG. 6 illustrates a functional block diagram of the beamforming controlmodule in accordance with an example embodiment;

FIG. 7 illustrates a side view of a plurality of base stationscorresponding to sky cells disposed adjacent to each other to provide acontinuous area where interference mitigation may be accomplishedaccording to an example embodiment;

FIG. 8 shows a top view of a network that may include a similarstructure to that described in reference to the network of FIG. 1,except that the network of FIG. 8 further comprises sky cells of anexample embodiment; and

FIG. 9 illustrates a block diagram of a method of communicating in anATG network in accordance with an example embodiment.

DETAILED DESCRIPTION

Some example embodiments now will be described more fully hereinafterwith reference to the accompanying drawings, in which some, but not allexample embodiments are shown. Indeed, the examples described andpictured herein should not be construed as being limiting as to thescope, applicability or configuration of the present disclosure. Rather,these example embodiments are provided so that this disclosure willsatisfy applicable legal requirements. Like reference numerals may beused to refer to like elements throughout. Furthermore, as used herein,the term “or” is to be interpreted as a logical operator that results intrue whenever one or more of its operands are true.

Some example embodiments described herein provide architectures forimproved air-to-ground (ATG) wireless communication performance. In thisregard, some example embodiments may provide for base stations havingantenna structures that facilitate providing wireless communicationcoverage in vertical and horizontal planes with sufficient elevation tocommunicate with aircraft at high elevations. A plurality of basestations may be distributed to provide a corresponding plurality ofadjacent wedge shaped cell coverage areas. Each wedge shaped cell maydefine a coverage area that extends between an upper and lower altitudelimit and the upper and lower altitude limits may increase(substantially linearly) as distance from the transmitters forming thewedge shaped cell increases. A plurality of sectors within each wedgeshaped cell may combine to form the wedge shaped cell. In some cases,six sectors may be employed to cover about 30 degrees each for a totalof 180 degrees of azimuth coverage provided by each wedge shaped cell.The cell coverage area may therefore be substantially semicircular inthe horizontal plane, and can be provided by multiple antennas eachproviding a wedge shaped sector over corresponding portions of thesemicircular azimuth. The base stations can be deployed as substantiallyaligned in a first direction while offset in a second direction. Forexample, the base stations can also be deployed in the first directionat a first distance to provide coverage overlapping in elevation toachieve coverage over the predetermined altitude, and within a seconddistance in the second direction based on an achievable coverage areadistance of the sectors.

FIG. 1 illustrates a top view of a network 100 of deployed base stationsfor providing ATG wireless communication coverage. Network 100 includesvarious base stations providing substantially semicircular cell coverageareas. The cell coverage areas are each depicted in two portions. Forexample, the cell coverage area for a first base station is shown assimilarly patterned portions 102 and 104. The portions 102 and 104represent a single continuous cell coverage area over a horizontalplane; however, FIG. 1 depicts intervening portion 108 of another cellcoverage area as providing overlapping coverage to achieve continuouscoverage up to a predetermined altitude, as described further herein.Portion 102 is shown to represent the initial cell coverage area fromthe location of the corresponding base station out to an arbitrarydistance for illustrative purposes; it is to be appreciated that thisportion 102 also includes the overlapping coverage of portion 108 ofanother cell coverage area to achieve coverage at the predeterminedaltitude. Moreover, the coverage area represented by portions 106 and108 may extend beyond boundary 130 of coverage area portion 104; thecoverage areas are limited in the depiction to illustrate at least onepoint where the bordering coverage areas are able to provide ATGwireless communication coverage at the predetermined altitude. Further,the base stations are not depicted for ease of explanation, but it is tobe appreciated that the base stations can be located such to provide thecell coverage area indicated by portions 102 and 104, portions 106 and108, portions 110 and 112, etc.

The cell coverage areas 102/104 and 106/108 can be provided byrespective base stations in a first base station array, where the basestations of one or more base station arrays are substantially aligned ina first direction 120 (as depicted by the representative cell coverageareas). As shown, cell coverage areas 102/104 and 106/108 project adirectional radiation pattern that is oriented in the first direction,and are aligned front to back along the first direction. Such alignmentcan be achieved by substantially aligning base stations in the basestation array to provide the substantially aligned cell coverage areas,antenna rotation to achieve alignment in the cell coverage areas in thefirst direction 120, and/or the like. As described, in this regard, afirst base station that provides cell coverage area 102/104 can beoverlapped by at least a cell coverage area 106/108 of a second basestation in front of the first base station in the first direction 120.For example, a base station, or antennas thereof, can provide wedgeshaped cell coverage areas defined by multiple elevation angles employedby antennas transmitting signals to achieve a predetermined altitude bya certain distance from the base station. Thus, overlapping the cellcoverage areas in the first direction 120 allows cell coverage area106/108 to achieve the predetermined altitude for at least the certaindistance between the base station providing cell coverage area 102/104and a point along line 130 where the cell coverage area 102/104 achievesthe predetermined altitude.

In addition, base stations in the first base station array providingcell coverage areas 102/104 and 106/108 can be spaced apart (i.e.,located at random, fixed or predetermined intervals) in a seconddirection 122 from base stations of a second base station array, whichcan provide additional cell coverage areas 110/112, 114/116, etc.,aligned in the first direction 120. The first and second base stationarrays can extend substantially parallel to each other in the firstdirection 120. In addition, base stations of the second base stationarray can be offset from base stations of the first base station arrayin the first direction 120 (as depicted by the representative cellcoverage areas). The second direction 122 can be substantiallyperpendicular to the first direction 120 in one example. In thisexample, the first and second base station arrays can be offset toprovide the offsetting of respective cell coverage areas (e.g., theoffset shown between cell coverage areas 102/104 and 110/112), and anyother coverage areas of the base station arrays aligned in the firstdirection 120.

The first and second base station arrays can be spaced apart at agreater distance in the second direction 122 than base stations withinthe respective arrays spaced apart in the first direction 120. Forexample, the base stations can be spaced in the second direction 122according to an achievable coverage distance of the base stationproviding the cell coverage areas. Because the base stations providingcell coverage areas 102/104 and 106/108 in the first base station arrayare aligned in the first direction 120 such that cell coverage area106/108 provides overlapping coverage to cell coverage area 102/104 toachieve the predetermined altitude, the base station arrays themselvescan be separated based on the achievable distance of the respective cellcoverage areas 102/104 and 110/112. In this regard, no substantialoverlapping is needed between the boundaries of cell coverage areas102/104 and 110/112 provided by base stations of adjacent base stationarrays to reach the predetermined altitude since the altitudedeficiencies near the respective base stations are covered by cellcoverage areas of base stations in the base station array aligned in thefirst direction 120.

Moreover, offsetting the base stations providing the various cellcoverage areas over the second direction 122 can allow for furtherspacing in the first direction 120 and/or second direction 122 as theend portions of one cell coverage area in the horizontal plane can abutto a middle portion of another cell coverage area from a base station inan adjacent base station array to maximize the distance allowed betweenthe cell coverage areas while maintaining continuous coverage, which canlower the number of base stations necessary to provide coverage over agiven area. In one example, the spacing in the second direction 122 canbe more than twice the spacing in the first direction 120, depending onthe coverage distance of the cell coverage areas and the distance overwhich it takes a cell coverage area to reach the predetermined altitude.

As depicted, the spacing of a first distance between base stations in agiven base station array can be indicated as distance 140 in the firstdirection 120. The spacing of a second distance between base stationarrays in the second direction 122 can be indicated as distance 142.Moreover, the offset between the base station arrays can be indicated asa third distance 144. In one specific example, the distance 140 can benear 150 kilometers (km), where distance 142 between the base stationsproviding cell coverage area 102/104 can be 400 km or more. In thisexample, the achievable cell coverage areas can be at least 200 km fromthe corresponding base station in the direction of the transmittedsignals that form the coverage areas or related sectors thereof.Moreover, in this example, the distance 144 can be around 75 km.

In an example, the base stations providing cell coverage areas 102/104,106/108, 110/112, etc. can each include respective antenna arraysdefining a directional radiation pattern oriented in the firstdirection. The respective antenna arrays can include multiple antennasproviding a sector portion of the radiation pattern resulting in acoverage area that is wedge shaped in the vertical plane. For example,the cell coverage area provided by each antenna can have first andsecond elevation angles that exhibit an increasing vertical beam widthin the vertical plane, and fills a portion of an azimuth in thehorizontal plane. Using more concentrated signals that provide smallerportions of the azimuth can allow for achieving further distance and/orincreased elevation angles without increasing transmission power. In thedepicted example, the cell coverage areas defined by the antenna arraysinclude six substantially 30 degree azimuth sectors that aresubstantially adjacent to form a directional radiation pattern extendingsubstantially 180 degrees in azimuth centered on the first direction todefine the semicircular coverage area. Each sector can be provided by anantenna at the corresponding base station, for example. Moreover, in oneexample, the base station can have a radio per antenna, a less number ofradios with one or more switches to switch between the antennas toconserve radio resources, and/or the like, as described further herein.It is to be appreciated that additional or a less number of sectors canbe provided. In addition, the sectors can have an azimuth more or lessthan 30 degrees and/or can form a larger or smaller total cell coveragearea azimuth than the depicted semicircular cell coverage area.

In yet other examples, the network 100 can implement frequency reuse oftwo such that adjacent base stations can use alternating channels inproviding the cell coverage areas. For example, a base station providingcell coverage areas 102/104 can use a first channel, and a base stationproviding cell coverage area 106/108 in the same base station array canuse a second channel. Similarly, the base station providing cellcoverage area 110/112 in a different base station array can use thesecond channel, etc. It is to be appreciated that other frequency reusepatterns and/or number of reuse factors can be utilized in this schemeto provide frequency diversity between adjacent cell coverage areas.

Furthermore, in an example deployment of network 100, the firstdirection 120 and/or second direction 122 can be, or be near, a cardinaldirection (e.g., north, south, east, or west), an intermediate direction(e.g., northeast, northwest, southeast, southwest, north-northeast,east-northeast, etc.), and/or the like on a horizontal plane. Inaddition, the network 100 can be deployed within boundaries of acountry, boundaries of an air corridor across one or more countries,and/or the like. In one example, cell coverage area 106/108 can beprovided by an initial base station at a border of a country or aircorridor. In this example, a base station providing cell coverage area106/108, 110/112, and/or additional cell coverage areas at the border,can include one or more patch antennas to provide coverage at thepredetermined altitude from the distance between the base station to thepoint where the respective cell coverage area 106/108, 110/112, etc.reaches the predetermined altitude. For example, the one or more patchantennas can be present behind the cell coverage areas 106/108, 110/112,etc., and/or on the base stations thereof (e.g., as one or more antennasangled at an uptilt and/or parallel to the horizon) to provide cellcoverage up to the predetermined altitude.

FIG. 2 illustrates an example network 200 for providing overlappingcells to facilitate ATG wireless communication coverage at least at apredetermined altitude. Network 200 includes base stations 202, 204, and206 that transmit signals for providing the ATG wireless communications.Base stations 202, 204, and 206 can each transmit signals that exhibit aradiation pattern defined by a first and second elevation angle such toachieve a predetermined altitude. In this example, base stations 202,204, and 206 provide respective wedge shaped cell coverage areas 212,214, and 216. The base stations 202, 204, and 206 can be deployed assubstantially aligned in a first direction 120 as part of the same basestation array, as described above, or to otherwise allow for aligningthe cell coverage areas 212, 214, and 216 in the first direction, suchthat cell coverage area 212 can overlap cell coverage area 214 (and/or216 at a different altitude range in the vertical plane), cell coveragearea 214 can overlap cell coverage area 216, and so on. This can allowthe cell coverage areas 212, 214, and 216 to achieve at least apredetermined altitude (e.g., 45,000 feet (ft)) for a distance definedby the various aligned base stations 202, 204, 206, etc.

As depicted, base station 202 can provide cell coverage area 212 thatoverlaps cell coverage area 214 of base station 204 to facilitateproviding cell coverage up to 45,000 ft near base station 204 for adistance until signals transmitted by base station 204 reach thepredetermined altitude of 45,000 ft (e.g., near point 130), in thisexample. In this example, base station 204 can be deployed at a positioncorresponding to the distance between which it takes cell coverage area214 of base station 204 to reach the predetermined altitude subtractedfrom the achievable distance of cell coverage area 212 of base station202. In this regard, there can be substantially any number ofoverlapping cell coverage areas of different base stations to reach thepredetermined altitude based on the elevation angles, the distance ittakes to achieve a vertical beam width at the predetermined altitudebased on the elevation angles, the distance between the base stations,etc.

In one specific example, the base stations 202, 204, and 206 can bespaced apart by a first distance 140, as described. The first distance140 can be substantially 150 km along the first direction 120, such thatbase station 204 is around 150 km from base station 202, and basestation 206 is around 300 km from base station 202. Further, in anexample, an aircraft flying between base station 206 and 204 may becovered by base station 202 depending on its altitude, and in oneexample, altitude can be used in determining whether and/or when tohandover a device on the aircraft to another base station or cellprovided by the base station.

Moreover, as described in some examples, base stations 202, 204 and 206can include an antenna array providing a directional radiation patternoriented along the first direction 120, as shown in FIG. 1, where thedirectional radiation pattern extends over a predetermined range inazimuth centered on the first direction 120, and extends between thefirst elevation angle and the second elevation angle of the respectivecoverage areas 212, 214, and 216 over at least a predetermined distanceto define the substantially wedge shaped radiation pattern. In thisregard, FIG. 2 depicts a side view of a vertical plane of the basestations 202, 204, and 206, and associated coverage areas 212, 214, and216. Thus, in one example, base station 202 can provide a cell coveragearea 212 that is similar to cell coverage area 106/108 in FIG. 1 in ahorizontal plane, and base station 204 can provide a cell coverage area214 similar to cell coverage area 102/104 in FIG. 1. Moreover, asdescribed, direction 120 can correlate to a cardinal direction,intermediate direction, and/or the like. In addition, in a deployment ofnetwork 200, additional base stations can be provided in front of basestation 206 along direction 120 until a desired coverage area isprovided (e.g., until an edge of a border or air corridor is reached).

FIG. 3 illustrates an example network 300 for providing overlappingcells to facilitate ATG wireless communication coverage at least at apredetermined altitude, as in FIG. 2. Network 300, thus, includes basestations 202, 204, and 206 that transmit signals for providing the ATGwireless communications. Base stations 202, 204, and 206 can eachtransmit signals that exhibit a radiation pattern defined by a first andsecond elevation angle such to achieve a predetermined altitude. Thisresults in providing respective wedge shaped cell coverage areas 212,214, and 216. The base stations 202, 204, and 206 can be deployed assubstantially aligned in a first direction as part of the same basestation array, as described above, or to otherwise allow for aligningthe cell coverage areas 212, 214, and 216 in the first direction, suchthat cell coverage area 212 can overlap cell coverage area 214 (and/or216), cell coverage area 214 can overlap cell coverage area 216, and soon. This can allow the cell coverage areas 212, 214, and 216 to achieveat least a predetermined altitude (e.g., 45,000 ft) for a distancedefined by the various aligned base stations 202, 204, 206, etc., asdescribed.

In addition, however, base station 202 can be deployed at an edge of adesired coverage area, and can include one or more patch antennas toprovide additional ATG wireless communication coverage. In an example,the edge of the desired coverage area can include a border of a country,an edge of an air corridor, etc. For example, the one or more patchantennas can be provided at an uptilt angle and/or with additionalelevation as compared to antenna(s) providing cell coverage area 202. Inone example, at least one patch antenna can provide additional coverageareas 302 and/or 304 up to the target altitude to fill coverage gapsnear the border or edge in the network deployment configurationdescribed herein, for example.

The network 100 and its corresponding base stations employing the wedgeshaped cell architecture described above in reference to FIGS. 1-3 maybe employed to provide coverage for communication with receivers onaircraft over a very large geographical area, or even an entire country.Moreover, using such an architecture may substantially reduce or evenminimize the number of base stations that are needed to construct thenetwork 100 since relatively large distances may be provided betweenbase stations. Beamforming techniques and frequency reuse may beemployed to further improve the ability of the network 100 to providequality service to multiple targets without interference. In one exampleembodiment, each wedge shaped cell may include six sectors (as mentionedabove) and each sector may be capable of forming at least threesimultaneous, non-overlapping full capacity beams to respectivereceivers on different aircraft. In some cases, the full capacity beamsmay provide at least 5 to 10 Mbps. Accordingly, each wedge shaped cellmay provide at least 15 to 30 Mbps per sector, and at least 90 to 180Mbps aggregate throughput to its corresponding coverage area.

If airborne interference from ground transmitters such as, for example,ground based WiFi transmitters were relatively low over the entirety ofthe geographic area to be covered, it could be expected that the wedgearchitecture of the network 100 of FIGS. 1-3 could provide robust andcost effective coverage without any further modification. However, asshown in FIG. 4, ground transmitters 400 may use omni-directionalantennas, or even antennas that are at least partially oriented totransmit upward, and these antennas may transmit potentially interferingsignal emissions 410 that may extend above metropolitan areas.Accordingly, an aircraft 420 traveling over the metropolitan area mayexperience a harsh communication environment. In some cases,particularly if the number and density of these ground transmitters ishigh, the amount of possible worst case interference may be difficult toovercome using just the network 100 topology described in reference toFIGS. 1-3. To facilitate overcoming harsh interference environments,such as those which may be present where a large number of groundtransmitters exist, some example embodiments may employ one or morevertically oriented cells (which may be referred to as “sky cells”).FIG. 4 illustrates one example of a vertically oriented cell 430.However, it should be appreciated that a plurality of such cells couldbe employed in certain large metropolitan areas and such cells may beplaced adjacent to each other to provide a wider area of interferencemitigation using the sky cell mitigation technique described herein.

In the example of FIG. 4, an illustration of a side view of the coveragearea of the vertically oriented cell 430 is provided. However, it shouldbe appreciated that this is a side view representation of the circularlypolarized antenna(s) forming the “sky cell”. Thus the coverage area ofthe vertically oriented cell 430 may be substantial cone shaped with theapex of the cone at the transmitter or base station forming thevertically oriented cell 430. In some cases, the tapering sides of thecone may define a 120 degree coverage area extending upward from thetransmitter or base station (e.g., sky cell base station 435) at theapex of the cone.

It should be understood that part or all of the area shown in FIG. 4 mayalso be within one or more sectors of a wedge shaped cell similar tothose illustrated in FIGS. 1-3. Thus, the substantially horizontallyoriented coverage area of the wedge shaped cells may overlap with thesubstantially vertically oriented coverage area of the verticallyoriented cells. It should be understood that, in some cases, thefrequency used for communication within the wedge shaped cell may bedifferent than the frequency used for communication within thevertically oriented cell 430 in order to prevent interference betweensignals transmitted by each respective cell. However, it may also bepossible for the same frequency to be employed by these overlappingcells based, for example, on interference mitigation strategies that maybe employed at the aircraft 420. For example, the aircraft 420 may havea first antenna or antenna array that is oriented to receive signalswith angles of arrival that are focused near the horizon. Sector 440 inFIG. 4 illustrates the range over which such signals may be received onthe aircraft 420 via the first antenna or antenna array. The aircraft420 may also have a second antenna or antenna array that is oriented tobe substantially downward looking. Sector 450 illustrates the range overwhich such signals may be received on the aircraft 420 via the secondantenna or antenna array. In some cases, the aircraft 420 may employmechanical shielding of some form to further enhance isolation betweenthe first antenna or antenna array and the second antenna or antennaarray.

As can be appreciated from FIG. 4, received signals in sector 440 maynot be likely to suffer interference from the ground transmitters 400below, but may be able to receive the substantially horizontallyoriented signals transmitted via the wedge shaped cells. Meanwhile,although received signals from sector 450 may suffer some interferencefrom the ground transmitters 400, the vertically oriented cell 430 mayemploy a focused steerable beam with greater link margin to overcome thenoise generated by the ground transmitters 400.

Given that there may be overlap between a coverage area of thevertically oriented cell 430 and a corresponding wedge cell coveragearea, in some cases, the aircraft 420 (or more particularly one or morereceivers thereon) may be handed over between the wedge cell and thevertically oriented cell 430. Such handover may be conducted to offloadtraffic from one busy cell to a less busy cell to deliver higher peakdata rates, or may otherwise be conducted to maximize performance. Insome cases, the receiver on the aircraft 420 may be configured tocompare, e.g., at routine, random or predetermined intervals, signalstrength or other criteria between the cells providing the substantiallyhorizontally oriented coverage area and the cells providing thesubstantially vertically oriented coverage area to select the best cellas the serving cell for a given period of time (e.g., until the nextcomparison is made).

In accordance with an example embodiment, a beamforming control modulemay be provided that employs both 2D knowledge of fixed base stationlocation and 3D knowledge of position information regarding a receivingstation on an aircraft to assist in application of beamformingtechniques. The beamforming control module of an example embodiment maybe physically located at any of a number of different locations withinan ATG communication network including either being located on theaircraft 420 (to control beamforming from aircraft antenna arrays)and/or at a base station (e.g., base station 435). FIG. 5 illustrates afunctional block diagram of an ATG communication network that may employan example embodiment of such a beamforming control module.

As shown in FIG. 5, the first BS 500 and second BS 502 may each be basestations of the ATG network 100. The ATG network 100 may further includeother BSs 510, and each of the BSs may be in communication with the ATGnetwork 100 via a gateway (GTW) device 520. The ATG network 100 mayfurther be in communication with a wide area network such as theInternet 530 or other communication networks. In some embodiments, theATG network 100 may include or otherwise be coupled to a packet-switchedcore network. It should also be understood that the first BS 500, thesecond BS 502 and any of the other BSs 510 may be either examples ofbase stations employing circularly polarized antennas oriented tocommunicate primarily in a vertical orientation (e.g., base station 435of FIG. 4) or examples of base stations of the wedge architecture ofFIGS. 1-3. Thus, handovers of receivers on aircraft may be accomplishedunder the control of the system shown in FIG. 5 in either directionbetween any such assets.

In an example embodiment, the ATG network 100 may include a networkcontroller 540 that may include, for example, switching functionality.Thus, for example, the network controller 540 may be configured tohandle routing calls to and from the aircraft 420 (or to communicationequipment on the aircraft 420) and/or handle other data or communicationtransfers between the communication equipment on the aircraft 420 andthe ATG network 100. In some embodiments, the network controller 540 mayfunction to provide a connection to landline trunks when thecommunication equipment on the aircraft 420 is involved in a call. Inaddition, the network controller 540 may be configured for controllingthe forwarding of messages and/or data to and from communicationequipment on the aircraft 420, and may also control the forwarding ofmessages for the base stations. It should be noted that although thenetwork controller 540 is shown in the system of FIG. 5, the networkcontroller 540 is merely an exemplary network device and exampleembodiments are not limited to use in a network employing the networkcontroller 540.

The network controller 540 may be coupled to a data network, such as alocal area network (LAN), a metropolitan area network (MAN), and/or awide area network (WAN) (e.g., the Internet 530) and may be directly orindirectly coupled to the data network. In turn, devices such asprocessing elements (e.g., personal computers, laptop computers,smartphones, server computers or the like) can be coupled to thecommunication equipment on the aircraft 420 via the Internet 530.

Although not every element of every possible embodiment of the ATGnetwork 100 is shown and described herein, it should be appreciated thatthe communication equipment on the aircraft 420 may be coupled to one ormore of any of a number of different networks through the ATG network100. In this regard, the network(s) can be capable of supportingcommunication in accordance with any one or more of a number offirst-generation (1G), second-generation (2G), third-generation (3G),fourth-generation (4G) and/or future mobile communication protocols orthe like. In some cases, the communication supported may employcommunication links defined using unlicensed band frequencies such as2.4 GHz or 5.8 GHz. Example embodiments may employ time division duplex(TDD), frequency division duplex (FDD), or any other suitable mechanismsfor enabling two way communication within the system.

As indicated above, a beamforming control module may be employed onwireless communication equipment at either or both of the network sideor the aircraft side in example embodiments. Thus, in some embodiments,the beamforming control module may be implemented in a receiving stationon the aircraft 420 (e.g., a passenger device or device associated withthe aircraft's communication system (e.g., a WiFi router)). In someembodiments, the beamforming control module may be implemented in thenetwork controller 540 or at some other network side entity.

FIG. 6 illustrates the architecture of a beamforming control module 600in accordance with an example embodiment. The beamforming control module600 may include processing circuitry 610 configured to provide controloutputs for generation of beams from an antenna array disposed at eitherthe aircraft 420 or one of the base stations based on processing ofvarious input information. The processing circuitry 610 may beconfigured to perform data processing, control function execution and/orother processing and management services according to an exampleembodiment of the present invention. In some embodiments, the processingcircuitry 610 may be embodied as a chip or chip set. In other words, theprocessing circuitry 610 may comprise one or more physical packages(e.g., chips) including materials, components and/or wires on astructural assembly (e.g., a baseboard). The structural assembly mayprovide physical strength, conservation of size, and/or limitation ofelectrical interaction for component circuitry included thereon. Theprocessing circuitry 610 may therefore, in some cases, be configured toimplement an embodiment of the present invention on a single chip or asa single “system on a chip.” As such, in some cases, a chip or chipsetmay constitute means for performing one or more operations for providingthe functionalities described herein.

In an example embodiment, the processing circuitry 610 may include oneor more instances of a processor 612 and memory 614 that may be incommunication with or otherwise control a device interface 620 and, insome cases, a user interface 630. As such, the processing circuitry 610may be embodied as a circuit chip (e.g., an integrated circuit chip)configured (e.g., with hardware, software or a combination of hardwareand software) to perform operations described herein. However, in someembodiments, the processing circuitry 610 may be embodied as a portionof an on-board computer. In some embodiments, the processing circuitry610 may communicate with various components, entities and/or sensors ofthe ATG network 100.

The user interface 630 (if implemented) may be in communication with theprocessing circuitry 610 to receive an indication of a user input at theuser interface 630 and/or to provide an audible, visual, mechanical orother output to the user. As such, the user interface 630 may include,for example, a display, one or more levers, switches, indicator lights,buttons or keys (e.g., function buttons), and/or other input/outputmechanisms.

The device interface 620 may include one or more interface mechanismsfor enabling communication with other devices (e.g., modules, entities,sensors and/or other components of the ATG network 100). In some cases,the device interface 620 may be any means such as a device or circuitryembodied in either hardware, or a combination of hardware and softwarethat is configured to receive and/or transmit data from/to modules,entities, sensors and/or other components of the ATG network 100 thatare in communication with the processing circuitry 610.

The processor 612 may be embodied in a number of different ways. Forexample, the processor 612 may be embodied as various processing meanssuch as one or more of a microprocessor or other processing element, acoprocessor, a controller or various other computing or processingdevices including integrated circuits such as, for example, an ASIC(application specific integrated circuit), an FPGA (field programmablegate array), or the like. In an example embodiment, the processor 612may be configured to execute instructions stored in the memory 614 orotherwise accessible to the processor 612. As such, whether configuredby hardware or by a combination of hardware and software, the processor612 may represent an entity (e.g., physically embodied in circuitry—inthe form of processing circuitry 610) capable of performing operationsaccording to embodiments of the present invention while configuredaccordingly. Thus, for example, when the processor 612 is embodied as anASIC, FPGA or the like, the processor 612 may be specifically configuredhardware for conducting the operations described herein. Alternatively,as another example, when the processor 612 is embodied as an executor ofsoftware instructions, the instructions may specifically configure theprocessor 612 to perform the operations described herein.

In an example embodiment, the processor 612 (or the processing circuitry610) may be embodied as, include or otherwise control the operation ofthe beamforming control module 600 based on inputs received by theprocessing circuitry 610 responsive to receipt of position informationassociated with various relative positions of the communicating elementsof the network. As such, in some embodiments, the processor 612 (or theprocessing circuitry 610) may be said to cause each of the operationsdescribed in connection with the beamforming control module 600 inrelation to adjustments to be made to antenna arrays to undertake thecorresponding functionalities relating to beamforming responsive toexecution of instructions or algorithms configuring the processor 612(or processing circuitry 610) accordingly. In particular, theinstructions may include instructions for processing 3D positioninformation of a moving receiving station (e.g., on an aircraft) alongwith 2D position information of fixed transmission sites in order toinstruct an antenna array to form a beam in a direction that willfacilitate establishing a communication link between the movingreceiving station and one of the fixed transmission stations asdescribed herein.

In an exemplary embodiment, the memory 614 may include one or morenon-transitory memory devices such as, for example, volatile and/ornon-volatile memory that may be either fixed or removable. The memory614 may be configured to store information, data, applications,instructions or the like for enabling the processing circuitry 610 tocarry out various functions in accordance with exemplary embodiments ofthe present invention. For example, the memory 614 could be configuredto buffer input data for processing by the processor 612. Additionallyor alternatively, the memory 614 could be configured to storeinstructions for execution by the processor 612. As yet anotheralternative, the memory 614 may include one or more databases that maystore a variety of data sets responsive to input sensors and components.Among the contents of the memory 614, applications and/or instructionsmay be stored for execution by the processor 612 in order to carry outthe functionality associated with each respectiveapplication/instruction. In some cases, the applications may includeinstructions for providing inputs to control operation of thebeamforming control module 600 as described herein.

In an example embodiment, the memory 614 may store fixed positioninformation 650 indicative of a fixed geographic location of at leastone base station. In some embodiments, the fixed position information650 may be indicative of the fixed geographic location of a single basestation of the ATG network 100. However, in other embodiments, the fixedposition information 650 may be indicative of the fixed geographiclocation of multiple ones (or even all) of the base stations of the ATGnetwork 100. In other embodiments, the fixed position information 650may be stored at another memory device either onboard the aircraft 420or accessible to the network controller 540. However, regardless of thestorage location of the fixed position information 650, such informationmay be read out of memory and provided to (and therefore also receivedat) the processing circuitry 610 for processing in accordance with anexample embodiment.

The processing circuitry 610 may also be configured to receive dynamicposition information 660 indicative of a three dimensional position ofat least one mobile communication station (which should be appreciatedto be capable of transmission and reception of signaling in connectionwith two way communication). The mobile communication station may be apassenger device onboard the aircraft 420, or may be a wirelesscommunication device of the aircraft 420 itself. The wirelesscommunication device of the aircraft 420 may transfer information to andfrom passenger devices (with or without intermediate storage), or maytransfer information to and from other aircraft communications equipment(with or without intermediate storage).

In an example embodiment, the processing circuitry 610 may be configuredto determine an expected relative position of a first network node(e.g., one of the base station or the mobile communication station)relative to a second network node (e.g., the other one of the basestation or the mobile communication station) based on the fixed positioninformation 650 and the dynamic position information 660. In otherwords, the processing circuitry 610 may be configured to utilizeinformation indicative of the locations of two devices or network nodesand determine where the network nodes are relative to one another fromthe perspective of either one of the network nodes (or both). Trackingalgorithms may be employed to track dynamic position changes and/orcalculate future positions based on current location and rate anddirection of movement. After the expected relative position isdetermined, the processing circuitry 610 may be configured to provideinstructions to direct formation of a steerable beam from an antennaarray of the second network node based on the expected relativeposition. The instructions may be provided to a control device that isconfigured to adjust characteristics of an antenna array (of either themobile communication station or the base station) to form directionallysteerable beams steered in the direction of the expected relativeposition. Such steerable beams may, for example, have azimuth andelevation angle widths of 5 degrees or less. Moreover, in some cases,such steerable beams may have azimuth and elevation angle widths of 2degrees or less. However, larger sized steerable beams may also beemployed in some embodiments.

In an example embodiment, the first network node may be disposed at (orbe) the base station, and the second network node may be disposed at themobile communication station (e.g., the aircraft 420 or communicationequipment thereon). However, alternatively, the first network node couldbe the mobile communication station, and the second network node couldbe at the base station. Furthermore, multiple instances of thebeamforming control module 600 may be provided so that both the mobilecommunication station and the base station may employ the beamformingcontrol module 600. Alternatively or additionally, multiple instances ofthe beamforming control module 600 may be provided on multiple aircraftand/or on multiple base stations so that each device (or at leastmultiple devices) within the ATG network 100 may be able to directsteerable beams toward other devices in the network on the basis ofusing position information to estimate the relative position of a deviceto focus a beam toward the expected or estimated relative position.

In some embodiments, regardless of where the beamforming control module600 is instantiated, determining the expected relative position mayinclude determining a future mobile communication station position andcorresponding estimated time at which the mobile communication stationwill be at the future mobile communication station position. In otherwords, the processing circuitry 610 may be configured to utilize thedynamic position information to not only determine a current position ofthe mobile communication station, but to further determine a futureposition of the mobile communication station so that, for example, theexpected relative position may be determined for some future time atwhich at beam may be focused based on the expected relative position toestablish a communication link with a moving aircraft or communicationequipment thereon.

In an example embodiment, the dynamic position information 660 mayinclude at least altitude information. Moreover, in some cases, thedynamic position information 660 may include latitude and longitudecoordinates and altitude to provide a position in 3D space. In somecases, the dynamic position information 660 may further include headingand speed so that calculations can be made to determine, based oncurrent location in 3D space, and the heading and speed (and perhapsalso rate of change of altitude), a future location of the aircraft 420at some future time. In some cases, flight plan information may also beused for predictive purposes to either prepare assets for futurebeamforming actions that are likely to be needed, or to provide planningfor network asset management purposes. In some embodiments, thebeamforming control module 600 may be disposed at the aircraft 420. Insuch cases, the fixed position information 650 may be provided formultiple base stations to define the network topology and may be storedin a memory device (e.g., memory 614) onboard the aircraft 420.

The dynamic position information 660 may be determined by any suitablemethod, or using any suitable devices. For example, the dynamic positioninformation 660 may be determined using global positioning system (GPS)information onboard the aircraft 420, based on triangulation of aircraftposition based on a direction from which a plurality of signals arriveat the aircraft 420 from respective ones of the base stations, usingaircraft altimeter information, using radar information, and/or thelike, either alone or in combination with each other.

In an example embodiment, the beamforming control module 600 may bedisposed at the network controller 540, which may be in communicationwith the base stations of the ATG network 100. In such an example, thebeamforming control module 600 may be configured to receive dynamicposition information 660 for a plurality of aircraft, and to provideexpected relative position information for each aircraft relative to oneof the base stations. Alternatively or additionally, the beamformingcontrol module 600 may be configured to receive dynamic positioninformation, and to provide expected relative position information forat least one aircraft relative to at least two base stations. In stillother embodiments, the beamforming control module 600 may additionallyor alternatively be configured to receive dynamic position information,and to provide multiple expected relative positions for respectivedifferent aircraft with respect to multiple base stations.

An instance of the beamforming control module 600 possessing some or allof the features described herein may be provided at any or all of theaircraft 420, the network controller 540 or at the cells base stationsthemselves. In an example embodiment, the aircraft 420 may be aware ofits own location and may also store all of the locations of the basestations as the fixed position information 650. Accordingly, theaircraft 420 may be able to project when it will be leaving one cellcoverage area to approach another, or when sky cell assistance may beavailable. The aircraft 420 (or an asset thereon that employs thebeamforming control module 600) may then determine in which direction anext base station for maintaining continuous and uninterruptedcommunication is located based on the current and expected futurelocations of the aircraft 420. The beamforming control module 600 maythen initiate contact with the next base station and supply the nextbase station with the dynamic position information 660 (including atleast the altitude of the aircraft 420). An instance of the beamformingcontrol module 600 either at or in communication with the next basestation may then, with fixed position information 650 indicative of atleast its own location and the dynamic position information 660received, determine a relative position of the aircraft 420 and direct asteerable beam toward the aircraft 420 based on the dynamic positioninformation 660.

In some example embodiments, the beamforming control module 600 mayfurther be configured to direct the usage of different frequencies forcommunicating with the aircraft 420 by beamforming using a frequencythat is selected on the basis of the altitude of the aircraft 420. Inthis regard, for example, to facilitate frequency reuse while mitigatinginterference impacts, the network controller 540 may be enabled to usethe beamforming control module 600 to form beams using a frequency thatis selected based on the altitude band in which the aircraft 420 isoperating. In particular, a plurality of altitude bands may be definedand a different frequency may be assigned to each respective altitudeband. When the dynamic position information is provided for the aircraft420, the altitude of the aircraft 420 may be known. Accordingly, thebeamforming control module 600 may be configured to form a beam to theaircraft 420 with a selected frequency that corresponds to the currentaltitude of the aircraft 420. FIG. 7 illustrates this concept in amanner that may enhance understanding of both the reasons for suchoperation and the mechanisms by which such operation is accomplished.

FIG. 7 illustrates a side view of a plurality of base stationscorresponding to sky cells (SC1, SC2, SC3, SC4, SC5 and SC6) disposedadjacent to each other to provide a continuous area where interferencemitigation may be accomplished according to an example embodiment. Thisconfiguration may be employed over an air corridor that passes over adense metropolitan area (e.g., having high levels of WiFi interference).The triangular cell coverage areas include area 710 corresponding to thearea served by SC1, area 720 corresponding to the area served by SC2,area 730 corresponding to the area served by SC3, area 740 correspondingto the area served by SC4, area 750 corresponding to the area served bySC5, and area 760 corresponding to the area served by SC6.

It should be appreciated that the conical coverage areas that can beprovided by the sky cells are represented as triangles in this twodimensional view. However, for dense metropolitan areas where adjacentsky cell placement is desired, the conical shaped cell coverage areasmay effectively terminate when a certain ground radius half way betweena next adjacent cell is reached. Thus, edges of the cell may effectivelyturn to straight vertical at the defined intersection. In an exampleembodiment, the diameter of a sky cell coverage area may be desirablymaintained at a minimum of about 20 km. However, other diameter sizescould be selected in some alternative embodiments.

Although the cells may effectively terminate at the cell edges, itshould be appreciated that an overlap region will be provided within anadjacent cell and, in some cases, overlap regions may include potentialcoverage areas from multiple cells. In this regard, overlap area 762corresponds to the overlap of area 760 and area 750. Meanwhile, overlaparea 764 represents the overlap of areas 740, 750 and 760. An aircraftlocated in overlap area 764 may therefore technically be reachable bythe SC4, SC5 or SC6. However, the beamforming control module 600 mayhave the fixed position information 650 of each of SC4, SC5 and SC6 toappreciate the boundaries therebetween, and the beamforming controlmodule 600 may also have the dynamic position information 660 indicatingthe altitude and location of the aircraft 420 within SC5. Thus, thebeamforming control module 600 may direct the SC5 to communicate withthe aircraft 420 while the aircraft is in the overlap area 764. Theknowledge of the location of the aircraft 420 relative to the geographicboundaries of the sky cells enables the sky cells to use relativelysteep (i.e., more vertical) beams to communicate with each aircraft inorder to minimize the transmissions from one SC in the coverage area ofanother SC.

Given the selected diameter of about 20 km, and the slope of theboundaries, it can be appreciated that the sky cells must be separatedby a specific distance in order to provide continuous coverage at aminimum continuous coverage altitude indicated by first altitude 770. Afirst altitude band may therefore be defined below the first altitude770. As shown in FIG. 7, a first frequency (F1) may be selected for useto communicate with any aircraft in the first altitude band. Anotheraltitude band (e.g., a second altitude band) having its owncorresponding operating frequency (e.g., second frequency (F2)) may bedefined between a second altitude 780 and the first altitude 770. Thesecond altitude may be above the first altitude 770 by a predeterminedamount. In some cases, still another altitude band (e.g., a thirdaltitude band) having its own corresponding operating frequency (e.g.,third frequency (F3)) may be defined above the second altitude 780. Asmentioned above, when the beamforming control module 600 receivesaltitude information for the aircraft 420, the beamforming controlmodule 600 may determine which altitude band the aircraft 420 is within.Then the beamforming control module 600 may select the correspondingfrequency for the altitude band in which the aircraft 420 is located. Inthe present example, the aircraft 420 may be in the third altitude bandat 40,000 ft. above SC1. Accordingly, the beamforming control module 600may direct SC1 to form a beam 790 toward the aircraft 420 using thethird frequency (F3).

By employing the methodology described above, different subchannels maybe employed in corresponding different altitude bands so that efficientspectrum utilization may be accomplished within a relatively densedeployment. By using a targeted beam, a relatively small amount ofenergy will be sent into any surrounding cells due to the steepelevation angle of the formed beam. Moreover, by selecting a relativelysmall cell size, the path loss to the airplane is reduced (e.g.,relative to the path loss for a potentially very long range wedge shapedcell) so the link budget closes. Thus, the possibility of interferencewith a target in an adjacent cell is reduced. Furthermore, since anyaircraft within the same coverage area would likely have altitudeseparation, the use of different frequencies for communication with theaircraft may ensure that there is also minimal chance of interference insuch scenarios. In some cases, the sky cells may each support at leastthree simultaneous beams that can therefore deliver at least about 6Mbps to as many as three aircraft simultaneously.

FIG. 8 shows a top view of a network 800 that may include a similarstructure to that described in reference to the network 100 of FIG. 1,except that FIG. 8 also shows a first sky cell 810 and a second sky cell820. The first sky cell 810 is collocated with a base station that alsoprovides one cell of the wedge architecture. The second sky cell 820 isnot collocated with abase station that also provides one cell of thewedge architecture. Thus, both potential deployment options areillustrated by example. However, it should be appreciated that multipleexamples of either option, or the absence of either option may also bepracticed in various example embodiments.

As such, the network 800 of FIG. 8 may provide an environment in whichthe control module of FIG. 6 may provide a mechanism via which a numberof useful methods may be practiced. FIG. 9 illustrates a block diagramof one method that may be associated with the system of network 800 ofFIG. 8 and the control module of FIG. 6. From a technical perspective,the beamforming control module 600 described above may be used tosupport some or all of the operations described in FIG. 9. As such, theplatform described in FIG. 6 may be used to facilitate theimplementation of several computer program and/or network communicationbased interactions. As an example, FIG. 9 is a flowchart of a method andprogram product according to an example embodiment of the invention. Itwill be understood that each block of the flowchart, and combinations ofblocks in the flowchart, may be implemented by various means, such ashardware, firmware, processor, circuitry and/or other device associatedwith execution of software including one or more computer programinstructions. For example, one or more of the procedures described abovemay be embodied by computer program instructions. In this regard, thecomputer program instructions which embody the procedures describedabove may be stored by a memory device of a device (e.g., the networkcontroller 540, a base station, the aircraft 420, a passenger or othercommunication device on the aircraft 420, and/or the like) and executedby a processor in the device. As will be appreciated, any such computerprogram instructions may be loaded onto a computer or other programmableapparatus (e.g., hardware) to produce a machine, such that theinstructions which execute on the computer or other programmableapparatus create means for implementing the functions specified in theflowchart block(s). These computer program instructions may also bestored in a computer-readable memory that may direct a computer or otherprogrammable apparatus to function in a particular manner, such that theinstructions stored in the computer-readable memory produce an articleof manufacture which implements the functions specified in the flowchartblock(s). The computer program instructions may also be loaded onto acomputer or other programmable apparatus to cause a series of operationsto be performed on the computer or other programmable apparatus toproduce a computer-implemented process such that the instructions whichexecute on the computer or other programmable apparatus implement thefunctions specified in the flowchart block(s).

Accordingly, blocks of the flowchart support combinations of means forperforming the specified functions and combinations of operations forperforming the specified functions. It will also be understood that oneor more blocks of the flowchart, and combinations of blocks in theflowchart, can be implemented by special purpose hardware-based computersystems which perform the specified functions, or combinations ofspecial purpose hardware and computer instructions.

In this regard, a method according to one embodiment of the invention,as shown in FIG. 9, may include receiving dynamic position informationindicative of at least an altitude of an in flight aircraft at operation900 and determining an altitude band in which the aircraft is locatedbased on the dynamic position information at operation 910. The methodmay further include determining a frequency associated with the altitudeband in which the aircraft is located at operation 920 and selecting thefrequency to conduct wireless communication with an asset on theaircraft at operation 930. In some embodiments, the method may furtherinclude additional optional operations, an example of which is shown indashed lines in FIG. 9. In this regard, for example, the method mayfurther include utilizing the dynamic position information to determinean expected relative position of the aircraft and providing instructionsto direct formation of a steerable beam based on the expected relativeposition at operation 940.

Many modifications and other embodiments of the inventions set forthherein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Moreover, although the foregoing descriptions and the associateddrawings describe exemplary embodiments in the context of certainexemplary combinations of elements and/or functions, it should beappreciated that different combinations of elements and/or functions maybe provided by alternative embodiments without departing from the scopeof the appended claims. In this regard, for example, differentcombinations of elements and/or functions than those explicitlydescribed above are also contemplated as may be set forth in some of theappended claims. In cases where advantages, benefits or solutions toproblems are described herein, it should be appreciated that suchadvantages, benefits and/or solutions may be applicable to some exampleembodiments, but not necessarily all example embodiments. Thus, anyadvantages, benefits or solutions described herein should not be thoughtof as being critical, required or essential to all embodiments or tothat which is claimed herein. Although specific terms are employedherein, they are used in a generic and descriptive sense only and notfor purposes of limitation.

What is claimed is:
 1. A beamforming control module for providingair-to-ground (ATG) wireless communication in various cells, thebeamforming control module comprising processing circuitry configuredfor: receiving dynamic position information indicative of at least analtitude of an in-flight aircraft, and a geographic location of thein-flight aircraft; determining an altitude band in which the aircraftis located based on the dynamic position information; determining, basedon a plurality of assigned ATG frequencies to respective differentaltitude bands, an ATG frequency associated with the altitude band inwhich the aircraft is located; selecting a base station having acoverage area associated with the geographic location, and selecting theATG frequency determined to conduct wireless communication with an asseton the aircraft; and providing both the geographic location and theselected ATG frequency to the selected base station to enable theselected base station to direct a steerable beam to the aircraft usingthe selected ATG frequency.
 2. The beamforming control module of claim1, wherein the beamforming control module is further configured todirect the steerable beam toward the aircraft via a circularly polarizedantenna array defining a substantially vertically extending radiationpattern.
 3. The beamforming control module of claim 1, wherein thebeamforming control module is further configured to select the basestation to direct the beam based on which one of a plurality of basestations is least likely to transmit into a coverage area of anotherbase station.
 4. The beamforming control module of claim 1, wherein thebeamforming control module is further configured to select a basestation to direct the beam based on knowledge of boundaries of coverageareas of adjacent base stations.
 5. The beamforming control module ofclaim 4, wherein the beamforming control module is further configured toselect the base station to direct the beam based on knowledge of overlapareas associated with adjacent base stations.
 6. The beamforming controlmodule of claim 1, wherein the beamforming control module is furtherconfigured to select the base station to direct the beam, the basestation defining a coverage area that is conical in shape having legs ofthe conical shape that are about 120 degrees apart.
 7. The beamformingcontrol module of claim 6, wherein multiple base stations definecoverage areas that are conical in shape having legs of the conicalshape that are about 120 degrees apart, and adjacent instances of themultiple base stations define cells having a diameter of about 20kilometers each.
 8. The beamforming control module of claim 1, whereinflight plan information is received by the beamforming control module,and wherein at least one base station to which the aircraft will behanded off in the future is predictively selected based on the flightplan information.
 9. The beamforming control module of claim 1, whereina future location of the aircraft is determined by the beamformingcontrol module, and wherein at least one base station to which theaircraft will be handed off in the future is predictively selected basedon the determined future location.
 10. An air-to-ground (ATG) wirelesscommunication network comprising: a plurality of cells associated withcorresponding base stations; and a beamforming control module forproviding ATG wireless communication in the cells, the beamformingcontrol module comprising processing circuitry configured to: receivedynamic position information indicative of at least an altitude of anin-flight aircraft, and a geographic location of the aircraft; determinean altitude band in which the aircraft is located based on the dynamicposition information; determine, based on a plurality of assigned ATGfrequencies to respective different altitude bands, an ATG frequencyassociated with the altitude band in which the aircraft is located;select one of the base stations having a coverage area associated withthe geographic location as a selected base station, and selecting theATG frequency determined to conduct wireless communication with an asseton the aircraft; and provide both the geographic location and theselected ATG frequency to the selected base station to enable theselected base station to direct a steerable beam to the aircraft usingthe selected ATG frequency.
 11. The ATG network of claim 10, wherein thebeamforming control module is further configured to direct the steerablebeam toward the aircraft via a circularly polarized antenna arraydefining a substantially vertically extending radiation pattern.
 12. TheATG network of claim 10, wherein the beamforming control module isfurther configured to select the base station to direct the beam basedon which one of the base stations is least likely to transmit into acoverage area of another base station.
 13. The ATG network of claim 10,wherein the beamforming control module is further configured to select abase station to direct the beam based on knowledge of boundaries ofcoverage areas of adjacent base stations.
 14. The ATG network of claim13, wherein the beamforming control module is further configured toselect the base station to direct the beam based on knowledge of overlapareas associated with adjacent base stations.
 15. The ATG network ofclaim 10, wherein the beamforming control module is further configuredto select the base station to direct the beam, the base station defininga coverage area that is conical in shape having legs of the conicalshape that are about 120 degrees apart.
 16. The ATG network of claim 15,wherein multiple base stations define coverage areas that are conical inshape having legs of the conical shape that are about 120 degrees apart,and adjacent instances of the multiple base stations define cells havinga diameter of about 20 kilometers each.
 17. The ATG network of claim 10,wherein flight plan information is received by the beamforming controlmodule, and wherein at least one base station to which the aircraft willbe handed off in the future is predictively selected based on the flightplan information.
 18. The ATG network of claim 10, wherein a futurelocation of the aircraft is determined by the beamforming controlmodule, and wherein at least one base station to which the aircraft willbe handed off in the future is predictively selected based on thedetermined future location.
 19. The ATG network of claim 10, wherein asecond set of base stations define wedge shaped cells that overlap eachother to provide coverage over a large geographical area, wherein theplurality of cells associated with the corresponding base stationsdefine substantially vertically oriented, conically shaped cells, andwherein one of the corresponding base stations is collocated with onebase station of the second set of base stations.
 20. The ATG network ofclaim 19, wherein another one of the corresponding base stations is notcollocated with any base station of the second set of base stations.